That's just philosophy and the same as saying no one ever does anything that's not for themselves.
Sometimes a player feels that a club has been good to them, and it makes the player happy to do something back for the club. That doesn't mean they'll suddenly work for free or ignore the chance...
My conclusion is that if we're promoted, he'll look at all the offers he receives, and choose the one that's best for him. I don't think it's particularly unlikely he'd sign for us, unless the management want to discourage others from running down their contracts, in which case he'll be off.